Understanding speaker basics.

[James]

Its actually a 3rd order on the tweeter...

In that case, it's the direction of the polar lobing that the designer intended. With odd-order XOs, the on-axis summation is the same regardless of relative polarity. But there will be a tilt to the polar response. This can be upwards or downwards, depending on the relative polarity.

My question is could I use that same Xover design for my tweeters???

It depends the extent to which the impedance curve of the new tweeter mirrors your existing ones and to what extent the existing filter has been designed to flatten things out. If the new tweeter has significantly different impedance, e.g. 4 ohms vs 8 ohms, then forget about it. The filter will not deliver anywhere near the same result.

James

 

[337alant]

James
Thanks again.

I realise I didnt ask the question very clearly, I wasen't wanting to change my tweeter just the Xover design,
The review was saying just what you said that you cant just change the Scanspeak 2905/950000 for the Scanspeak 2905/970000 and keep the same Xover as allthough they seem very similar in specs the perform differently. what I was trying to ask was that in the review there was two designs for the same Scanspeak 2905/950000 tweeter, the first was similar to the one in my speaker and the second was an improved one that gave a flatter response, so I was wondering if I could use that improved version in my speaker?

Captin sorry to crap your thread mate I will shut up now

 

[James]

... what I was trying to ask was that in the review there was two designs for the same Scanspeak 2905/950000 tweeter, the first was similar to the one in my speaker and the second was an improved one that gave a flatter response, so I was wondering if I could use that improved version in my speaker?

There are many filter configurations that can effect the same crossover, albeit with subtle differences. My very own E-IIIs have seen three different configurations, all yielding the same 2nd order Linkwitz-Riley acoustic crossover at 3.5kHz, but all three sounding slightly different.

If your current XO is identical to the one Troels had, then the 'improved' filter should work. Quite often, the slight tweak in frequency response is intended to help phase alignment, and I guess yours might either benefit from it or suffer for it, depending on how optimised it is currently. Certainly, my latter E-IIIR tweeter tweaks were to bring the phase to line up perfectly with the changed midrange driver.

Are you using the same midbass as Troels?

James

 

[337alant]

James,
MMM, no I am not and thats a good point actually as the Xover could be at a different frequency. looks like I should stick with what I have as it is actually got a good treble anyway.
My woofer is a Volt BM 220.8

Just noticed something else the woofer has a sens of 88db and the tweeter is 90db hence the 3ohm series resister in my hi pass filter, that Xover is ment for 90db I think

PS your ergos look awesome

Alan

 

[mudlark]

If you want to change a driver, I would recommend Wilmslow Audio. I have enjoyed three projects of theirs.